To investigate the association between helicobacter pylori (H.pylori) infection and the prevalence of Crohn's disease (CD).

107 patients who diagnosed as CD were selected.H.pylori infection was detected by rapid urea test by endoscopy.H.pylori infection rate was compared between CD group and control group, followed by a subgroup analysis based on lesion position of CD.

There were 107 patients in the CD group and 92 patients in the control group.There were no statistically significant differences in age, sex and BMI between the CD group and control group(all P>0.05). However, the CD group showed significantly higher rates of smoking history(37.38%) and alcohol intake (19.63%) compared with the control group(χ²=7.40, P<0.01; χ²=7.64, P<0.01). The H. pylori infection rate in the CD group was 28.97%, which was significantly lower than 60.87% in the control group(χ²=20.46, P<0.01). The H. pylori infection rate in the four subgroups were also significantly lower than those in the control group(χ²=6.88, P<0.01; χ²=5.48, P<0.05; χ²=13.44, P<0.01; χ²=7.20, P<0.01). However, there was no statistically significant difference in the H. pylori infection rate among these four subgroups(χ²=0.15, P=0.98).

H. pylori infection may play a protective role in the patients with CD and there is no significant association between potential protective effect and the change of lesion position.

Crohn disease; Helicobacter pylori; Inflammation mediators